Josiah s



(No Model.)

J. S. DU BOIS.

DYNAMO ELECTRIC MACHINE. No. 318,094. Patented May 19, 1885.

NITED STATES PATENT Orrrca.

JOSIAH S. DU BOIS, OF CAMDEN, NEXV JERSEY.

DYNAMO-ELECTRIC MACHINE.

SPECIFICATION forming part of Letters Patent No. 318,094, dated May 19,1885.

Application filed September 27, 1884.

To aZZ whom it may concern.-

Be it known that I, JOSIAH S. DU Bors, of the city and county of Camden,and State of New J ersey, have invented a new and useful Improvement inDynamo-Electric Machines, of which the following is a specification.

My invention has reference to a dynamoelectric machine; and it consistsin an air-tight casing or box inclosing the armature and, if desired,the entire poles of the field-magnets, in which casing a partial vacuumis maintained-the greater the vacuum the better; further, in combiningwith the foregoing suitable vacuum-creating devices, by which the vacuumin said casing may be maintained, and in many details of construction,all of which are fully set forth in the following specification, andshown in the accompanying drawings, which form part thereof.

heretofore it has been customary to cause a circulation of air throughthe armature and field-magnets of dynamo-electric machines to carry offthe heat, and it has also been customary to cause a constant circulationof cold water about the poles of the fieldniagnets. By my construction Iam enabled to rotate the armature in a vacuum, and thereby overcome theresistance offered by the air, obviating the necessary friction of thearmature in heat ing upon the air, and thereby reducing the consequentheat to a minimum.

Figure 1 is a side elevation of a dynamoelectric machine embodying myimprovement, with part of the casing broken away. Fig. 2 is a sectionalelevation of same 011 line a 00. Fig. 3 is a plan view showing therelative arrangement of a series of dynamo electric machines made inaccordance with my invention and the vacuum-creating mechanism.

A represents the dynamo-electric machine, in which B B are the two polesof the fieldmagnets, O them-mature, and O the armatureshaft.

Dis the casing, which is preferably made of brass, and is adapted toinclose the armature and, preferably, that portion of the field-magnetpoles which is adjacent to the armature. The said box or casing is madeto fit around the armature-shaft of one end, and upon the other end itmay fit a metallic ring, L, which is supported upon a disk ofnon-conducting material as hard rubber,

(No model.)

and may, if desired, inclose the commutator itself, the particularconstruction or method of attachment varying in accordance with theparticular make of machine to which the invention is applied. The saidcasing may have an air-tight cover, E, which may be clamped down by ahand-screw, H, which works through a pivoted strap, G, or, if desired,this cover may be simply screwed down.

, I is a pipe connecting with the vaeuunrcreating devices, and by whichthe air in the box or casing B is exhausted.

This invention is particularly adapted to stations where there are alarge number of dynamo-electric machines, as shown in Fig. 3, and thenthe pipes I connecting with the main M, through which the air isexhausted by the vacuum-pump N; and the amount of vacuum may becontrolled in each machine by valves 1, or these valves may be used tosimply cut off any machine not in use, and thereby reduce the dutyrequired of the vacuum-pump N.

Having now described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. A dynamo-electric machine having its armature inclosed within a casein which a partial vacuum is maintained, substantially as and for thepurpose specified.

2. A dynamo-electric machine having its armature and poles of itsfield-magnets inclosed within a stationary casein which a partial vacuumis maintained, substantially as and for the purpose specified.

3. A dynamo-electric machine having its armature inclosed within acase-in which a partial vacuum is maintained, in combination withvacuum-creating mechanism and connecting-pipes, substantially as and forthe purpose specified.

i. The combination of a series of dynamoelectric machines, having theirarmatures inclosed in vacuum-boxes, with pipes I, main J, andvacuum-pump N, substantially as and for the purpose specified.

5. The combination of a series of dynamoelectric machines, having theirarmatures in closed in vacuum-boxes, with pipes I, valves 1, main J, andvacuum-pump N, substan- I sulator-disk J, and wires K, passing to thetialy as and for the purpose specified.

6. A dynamo-electric machine provided with an air-tight case, inclosingthe armature, 5 in which a partial vacuum is maintained, and

a removable cover or door to said case, substantially as and for thepurpose specified.

7. The combination, in a dynamo-electric machine, of field-magnet polesB, armature C, 10 shaft 0', vacuum-case D, metallic ring L, in-

commutator, substantially as and for the purpose specified.

In testimony of which inventionlhereunto set my hand.

JOSIAH S. DU BOIS.

Witnesses:

R. M. HUNTER, WILLIAM G. MAYNE.

